AIG is best known in Britain as the shirt sponsor of Manchester United. Photograph: Matthew Peters/Getty Images

Troubled insurer AIG, kept alive last year by a $180bn (£107bn) US government bailout, has crept back into the black with a quarterly profit of $1.82bn despite weak underwriting earnings as its core business suffered damage from the group's well-publicised financial hardship.

News of the company's first profit for six quarters sent AIG's shares up 11% during early trading on Wall Street. The group, best known in Britain as Manchester United's shirt sponsor, was the largest insurance company in the world until it suffered catastrophic losses on complex financial derivatives.

The company has been battered by controversy over bonuses for executives at its disastrously performing financial products division and over the use of taxpayers' money to finance an expensive get-together for salesmen at a lavish Californian beachside hotel.

In an effort to avoid the stigma surrounding its financial woes, AIG has been downplaying the use of its brandname. But premiums written in its general insurance division still fell by 19.2% to $7.9bn, hit by the weak economy, a decision to defend pricing and "the effect of AIG's challenges on the business across the entire portfolio".

The company has sold assets to raise money. It has offloaded a life insurance business for $680m and a subsidiary called 21st Century Insurance for $1.9bn. The sale of an office block housing AIG's Japanese headquarters in Tokyo raised $1.2bn.

Michael Holland, a money manager at Holland & Co, said: "The reality is that the numbers are getting better and as a result it could be viewed as a potentially constructive first step towards financial success."

At the end of June, AIG owed $44.8bn to the Federal Reserve Bank of New York and had drawn down $1.2bn from a $29.8bn credit line from the treasury. It also had $41.6bn of preference shares outstanding.

The roots of AIG's difficulties lie in its financial products arm, largely run out of an office in Mayfair, which developed a niche in insuring financial institutions against the risk of default on seemingly low-risk derivatives including mortgage-backed securities. When the credit crunch began, AIG found itself facing huge claims on these policies which it struggled to pay.

Since its bailout, AIG has been gradually dismantling this division. The sum total of its derivatives portfolio dropped from $1.6tn in December to $1.3tn in June.

Liddy is due to stand down next week to make way for a former MetLife insurance boss, Robert Benmosche, who will become AIG's fifth chief executive since 2005.

Earlier this week, another dark chapter closed in AIG's history as the company's former boss, Hank Greenberg, paid $15m to the Securities and Exchange Commission to settle an investigation into accounting irregularities between 2000 and 2005.